The present invention relates to methods for producing a thin transparent panel which deflects light. While there are many uses for a panel which deflects light the embodiments of the invention described here are directed particularly to using a light deflecting panel as a window in the facade of a building for the purpose of deflecting incoming daylight upwards so that the ceiling of the building is illuminated thereby improving the natural lighting deep within the interior of the building.
The conventional means of deflecting light is by refraction in a prism of transparent material or by reflection from a metallic surface. Methods for producing transparent panels which deflect light usually utilise one or both of these means of deflecting light. In particular a light deflecting panel may be produced by moulding the surface of a sheet of glass or plastic into the form of prisms. Prismatic panels so formed have been used as focusing elements in optical systems, and as panels for diffusing light and as panels for deflecting daylight towards the interior of buildings. Reference to prismatic panels for daylighting is U.S. Pat. No 4,557,565 to Ruck et al. Prismatic sheets are deficient in that, with prismatic sheets, it is difficult to deflect light by more than about 45 degrees. For the deflection of sunlight towards the ceiling of a building deflection through angles greater than 45 degrees is frequently required. Two further deficiences of prismatic panels as windows for improving daylighting within buildings are, firstly, that the view through prismatic panels is severely distorted and secondly, that the surface of prismatic panels is difficult to clean.
Metallic reflectors have been used to form light deflecting window panels for improved daylighting in buildings by incorporating a plurality of plane or curved metal reflectors in the form of venetian blinds inside a window or between the panes of a double glazed window. Venetian blind reflectors are deficient in that the amount of light reflected depends strongly on the angle of incidence of the light and the reflecting surfaces are difficult to clean. References to metallic reflectors as light deflecting window panels are U.S. Pat. No. 4,699,467 to Bartenbach et al and U.S. Pat. No. 4,509,825 to Otto et al.
The object of the present invention is to provide a method for producing a thin transparent light deflecting panel able to deflect light through angles greater than 90 degrees and suitable for adaptation as a window panel which deflects incoming daylight upwards so that the ceiling of a building is illuminated thereby improving the natural lighting within the building.
Another objective of the present invention is to produce a light deflecting panel which is suitable for viewing through.
Another objective is to produce a light deflecting panel which is as thin as a conventional window panel and is as easy to clean.